Vibrator for loose materials, particularly concrete



Nov. 22, 196 o. PELLEGATTl VIBRATOR FOR LOOSE MATERIALS, PARTICULARLY CONCRETE Filed June 4., 1964 United States Patent 3,286,991 VIBRATOR FOR LOOSE MATERIALS, PARTICULARLY CONCRETE Olivo Pellegatti, Via Oslavia 27, Milan, Italy Filed June 4, 1964, Ser. No. 373,138 Claims priority, application Italy, June 14, 1963, 697,919/63 7 Claims. (Cl. 259-1) The present invention relates to a vibrating device for vibrating concrete and other loose materials.

As it is known, many advantages are achieved if the concrete used for forming building elements, either reinforced or not, is subjected to vibrations after casting and before hardening.

Vibrators are used for such purposes, as immersion into a concrete mass, to impart vibrations to the same. Such devices used at present, however, show certain drawhacks for instance, those including an oscillating mass striking an outer wall during its circular movement, and do not provide constantly uniform vibration; vibrators including a speed multiplying gearing directly coupled with a motor and connected to the vibrator through a flexible shaft submit the latter to excessive stress.

The device according to the present invention eliminates these and other inconveniences; in this device the flexible shaft revolves at the same speed of the motor, which is a conventional motor with comparatively low rotary speed; the device does not include oscillating masses, has very small transversal dimensions, is of simple, sturdy, compact and long-lasting construction and can be used therefore by non skilled operators.

The device according to the present invention is characterized by comprising, in a casing forming the body of the vibrator, an internal gear rim rotatably mounted on its own axis and provided with means for its connection to a flexible driving shaft, which gear engages a plurality of pinions equal to one another rotatably supported by pivots fixed with respect to said casing, said pinions engaging in turn another pinion supported for rotation on said axis and rigidly fixed to a mass eccentric with respect to said axis.

The device according to the present invention will be hereinafter described in one embodiment which is given by way of non limiting example only, the constructional details being variable, yet remaining in the socpe of the invention.

The example now described is represented in the accompanying drawings, in which:

FIG. 1 represents an axial section of a vibrator device according to the invention,

FIG. 2 shows the cross section through the line H-lI of the gearing of FIG. 1, and

FIG. 3 is a cross section through the line III-III of FIG. 1.

With reference to the above figures, the device according to the invention taken as example of practical embodiment comprises a casing 1, which is the vibrating body, closed at one end 2 and provided at the other end 3 with a cover 4 through which a tail shaft 5 rotatably supported by two ball bearings 6 passes with a fluid-tight arrangement. Said tail shaft 5 is integral with a cup-shaped hollow body 7 provided with internal teeth 8, which is arranged concentrically to the casing 1 and freely rotatable therein.

A disc member 15 is held in place within the casing 1 by means of an elastic split ring 26 and keeps in its seat within the casing 1 a ball bearing 16, the function of which will be explained hereinafter.

Bolts 17 are screwed in the disc member 15 and lock thereon a cage member 12 through the ring 13.

3,286,991 Patented Nov. 22, 1966.

The cage member 12 supports three pivots 11 fixed therein, which are connected to one another also by the ring 13. The pivots 1, through the small rollers or needles 14, support in a freely rotatable manner the pinions 9, equal to 'one another, all of which intermesh with the aforesaid toothed rim 8 and, at the same time, with a pinion 10 fixed through its pivot 19 to the end 21 of a shaft 20 freely rotatable in the casing 1 and supported at its end 21 by the bearing 16 and at its other end by a bearing 23 also mounted within the casing 1.

As it appears from the sectional view of the shaft 20 in FIG. 3, this shaft, which is substantially cylindrical, is provided with longitudinal recesses 24 extending substantially all its length, on one side with respect to a plane passing through the axis of the shaft, the trace of which is indicated by 25; the recesses have the purpose of making the mass of the shaft 20 eccentric so that its center of gravity is at a distance laterally from the axis 25. Thus, through the rotation of the eccentric mass of the shaft 20, the required vibrations are generated in the casing 1 and are transmitted to the material to be vibrated.

It is to be noted that according to the invention the flexible driving shaft (not represented) which is connected by one of its ends to the tail shaft 5 and by its other end to a conventional motor, is rotated by the latter at a comparatively low rotary speed (e.g. 2800 r.p.m.), which is the speed of the motor, while the eccentric mass shaft 20, driven by the tail shaft 5 with the intermediary of interposed gearing 9-10, rotates at a very high speed (e.g. 10,000-12,000 r.p.m.); the shaft 20, since it is supported by bearings fixed inside the casing 1, does not produce undesirable vibration in the flexible shaft, the rotation of which is comparatively slow, and therefore the device can be easily and safely handled by anybody without inconvenience.

On the other hand an important feature is that the speed increasing gearing does not include any mass rotating on a shaft not passing through its center of gravity, such as the satellites in an epicyclic gearing which, with the speeds required in vibrators of the kind considered, would induce such high stresses in their pivots as to jeopardize the structural integrity of the tool or require a cumbersome, heavy and costly construction. The apparatus according to the invention, on the contrary, has very small transversal dimensions and affords a safe, longlasting operation.

As it will appear to those skilled in the art, the shaft 20 may have a cross-section geometrically different from the preferred circular cross-section with recesses hereabove described as an example, provided that its mass is eccentric through the major part of its length.

Although only one embodiment of the device according to the invention has been described, as already stated, other modifications are possible in addition to those mentioned above, provided that the general concept of the invention is maintained, without departing from its scope as defined in the attached claims.

What is claimed is:

1. A vibrator device comprising a casing constituting a vibrating body, a hollow body adapted for being driven by a flexible drive cable and mounted for rotation relative to the casing, said hollow body having an internal toothed surface, a plurality of pivots secured in fixed position from the casing in an annular array, pinions of identical form mounted on said pivots for rotation thereabout, said pinions being in mesh with the internal toothed surface of the hollow body to be driven thereby, a shaft mounted in the casing for rotation about a predetermined axis, said shaft having a center of gravity which is oflset from said axis of rotation to produce vibration of the casing as the shaft rotates, and a further pinion secured with the shaft for coaxial .rotation therewith and centrally mounted within the aforesaid pinions and in meshing engagement therewith.

2. A vibrator device as claimed in claim 1 comprising means securing the pivots from the casing including a ring coaxially secured with the casing, a cage member coaxially secured within the casing in spaced relation with the ring, said pivots having opposite ends respectively mounted in the ring and cage member.

3. A vibrator device as claimed in claim 2 wherein the means securing the pivots from the casing further comprises an annular disc secured to the casing andfastencr means connecting the ring to the disc, said disc being positioned on a side of the cage member opposite the ring, said fastener means passing through the cage member.

4.. A vibrator device as claimed in claim 3 comprising a cap mounted on the casing and enclosing the hollow body and the pinions, said ring being mounted within the hollow body.,

5. A vibrator device as claimed in claim 4 wherein the 7. A vibrator device as claimed in claim 1 comprising means securing the pivots from the casing for removal and replacement therein.

References Cited by the Examiner UNITED STATES PATENTS 2,293,962 8/ 1942 Baily. 2,678,195 5/1954 Hunter. et a1.

FOREIGN PATENTS 820,953 4/ 1937 France; 708,670 7/ 1941 Germany.

WALTER A. SCHEEL, Primary Examiner.

20 R. W. JENKINS, Assistant Examiner. 

1. A VIBRATOR DEVICE COMPRISING A CASING CONSTITUTING A VIBRATING BODY, A HOLLOW BODY ADPATED FOR BEING DRIVEN BY A FLEXIBLE DRIVE CABLE AND MOUNTED FOR ROTATION RELATIVE TO THE CASING, SAID HOLLOW BODY HAVING AN INTERANL TOOTHED SURFACE, A PLURALITY OF PIVOTS SECURED IN FIXED POSITION FROM THE CASING IN AN ANNULAR ARRAY, PINIONS OF IDENTICAL FORM MOUNTED ON SAID PIVOTS FOR ROTATION THEREABOUT, SAID PINIONS BEING IN MESH WITH THE INTERNAL TOOTHED SURFACE OF THE HOLLOW BODY TO BE DRIVEN THEREBY, A SHAFT MOUNTED IN THE CASING FOR ROTATION ABOUT A PREDETERMINED AXIS, SAID SHAFT HAVING A CENTER OF GRAVITY WHICH IS OFFSET FROM SAID AXIS OF ROTATION TO PRODUCE VIBRATION OF THE CASING AS THE SHAFT ROTATES, AND A FURTHER PINION SECURED WITH THE SHAFT FOR COAXIAL ROTATION THEREWITH AND CENTRALLY MOUNTED WITHIN THE AFORESAID PINIONS AND IN MESHING ENGAGEMENT THEREWITH. 